Add 5G connection type in network_change_notifier_mac.

5G connection type is not added in network_change_notifier_mac.mm
currently. It leads to crash in Cronet when testing 5G network on iOS
(b/171830601).

Change-Id: I781ef9a253ff0e473fba7eceaf549ef2bc011c83
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2506300
Commit-Queue: Yu Su <yuyansu@google.com>
Reviewed-by: David Schinazi <dschinazi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822014}

net/base/network_change_notifier_mac.mm

@@ -113,6 +113,10 @@ NetworkChangeNotifierMac::CalculateConnectionType(
                               CTRadioAccessTechnologyeHRPD, nil];
     NSSet<NSString*>* technologies_4g =
         [NSSet setWithObjects:CTRadioAccessTechnologyLTE, nil];
+    // TODO: Use constants from CoreTelephony once Cronet builds with XCode 12.1
+    NSSet<NSString*>* technologies_5g =
+        [NSSet setWithObjects:@"CTRadioAccessTechnologyNRNSA",
+                              @"CTRadioAccessTechnologyNR", nil];
     int best_network = 0;
     for (NSString* service in service_current_radio_access_technology) {
       if (!service_current_radio_access_technology[service]) {
@@ -128,6 +132,8 @@ NetworkChangeNotifierMac::CalculateConnectionType(
         current_network = 3;
       } else if ([technologies_4g containsObject:network_type]) {
         current_network = 4;
+      } else if ([technologies_5g containsObject:network_type]) {
+        current_network = 5;
       } else {
         // New technology?
         NOTREACHED();
@@ -145,6 +151,8 @@ NetworkChangeNotifierMac::CalculateConnectionType(
         return CONNECTION_3G;
       case 4:
         return CONNECTION_4G;
+      case 5:
+        return CONNECTION_5G;
       default:
         // Default to CONNECTION_3G to not change existing behavior.
         return CONNECTION_3G;